Transformer and flat panel display device including same

Abstract

A transformer according to one embodiment comprises: a core portion having an upper core and a lower core; and a coil portion disposed in the core portion, wherein: the coil portion includes a first coil wound in a first direction, a second coil wound in a second direction opposite to the first direction, and a third coil including a flat panel shape; the lower core includes a body portion, a first leg portion and a second leg portion protruding from the body portion, and a spacing portion formed between the first leg portion and the second leg portion; the first leg portion includes two first outer legs and a first intermediate leg disposed between the two first outer legs; the second leg portion includes two second outer legs and a second intermediate leg disposed between the two second outer legs; the first coil can be disposed to surround the first intermediate leg; and the second coil can be disposed to surround the second intermediate leg.

1 . A transformer comprising:
 a core unit having an upper core and a lower core; and   a coil unit disposed in the core unit,   wherein the coil unit comprises:   a first coil wound in a first direction;   a second coil wound in a second direction, the second direction being opposite the first direction; and   a third coil having a flat plate shape,   wherein the upper core comprises:   a body portion;   a first leg portion and a second leg portion protruding from the body portion; and   a spacing portion formed between the first leg portion and the second leg portion,   wherein the first leg portion comprises two first outer legs and a first center leg disposed between the two first outer legs,   wherein the second leg portion comprises two second outer legs and a second center leg disposed between the two second outer legs,   wherein the first coil is disposed to surround the first center leg, and   wherein the second coil is disposed to surround the second center leg.   
     
     
         2 . The transformer according to  claim 1 , wherein the second coil is disposed on the first coil such that a portion of the second coil overlaps the first coil in a thickness direction. 
     
     
         3 . The transformer according to  claim 2 , comprising:
 an insulating layer disposed between the first coil and the second coil.   
     
     
         4 . The transformer according to  claim 11 , comprising:
 an insulating layer disposed between the first coil and the third coil.   
     
     
         5 . The transformer according to  claim 1 , wherein at least one of the first coil to the third coil has a portion protruding outwards beyond the core unit. 
     
     
         6 . The transformer according to  claim 1 , wherein the two first outer legs and the two second outer legs are disposed parallel to each other on a plane, and
 wherein the first center leg and the second center leg are disposed parallel to each other on a plane.   
     
     
         7 . The transformer according to  claim 1 , wherein the first leg portion has a total planar area greater than a total planar area of the second leg portion. 
     
     
         8 . The transformer according to  claim 6 , wherein a ratio of planar areas of the two first outer legs to a planar area of the first center leg or a ratio of planar areas of the two second outer legs to a planar area of the second center leg is 0.65 to 0.8. 
     
     
         9 . The transformer according to  claim 1 , wherein a ratio of a planar area of the second leg portion to a planar area of the core unit is 0.04 to 0.08. 
     
     
         10 . The transformer according to  claim 1 , wherein at least one of the upper core or the lower core has a recess formed between the first center leg and the second center leg. 
     
     
         11 . The transformer according to  claim 2 , wherein the third coil is disposed to surround the first center leg. 
     
     
         12 . The transformer according to  claim 1 , wherein the first coil and the second coil have ends led out toward a first side, and
 wherein the third coil has ends led out toward a second side, the second side being opposite the first side.   
     
     
         13 . The transformer according to  claim 1 , comprising:
 a bobbin disposed in the core unit.   
     
     
         14 . The transformer according to  claim 1 , comprising:
 a core shorting unit configured to electrically short the upper core and the lower core.   
     
     
         15 . The transformer according to  claim 1 , wherein the lower core is formed to be symmetrical to the upper core in a vertical direction, and
 wherein when the upper core and the lower core are coupled to each other, a gap is formed between at least one pair among the two pairs of center legs facing each other and the four pairs of outer legs facing each other.   
     
     
         16 . The transformer according to  claim 1 , wherein the third coil is formed such that a plurality of conductive metal plates having planar shapes bilaterally symmetrical to each other are stacked on each other. 
     
     
         17 . The transformer according to  claim 16 , wherein each of the plurality of conductive metal plates has a central end portion shorted in a center tap structure. 
     
     
         18 . The transformer according to  claim 1 , comprising:
 a heat dissipation unit disposed in an open region of at least one of the upper core and the lower core.   
     
     
         19 . The transformer according to  claim 18 , wherein the heat dissipation unit extends outside the core unit. 
     
     
         20 . A circuit board comprising:
 a substrate;   a circuit portion formed on the substrate; and   a transformer conductively connected to the circuit portion,   wherein the transformer comprises:   a core unit having an upper core and a lower core; and   a coil unit disposed in the core unit,   wherein the coil unit comprises:   a first coil wound in a first direction;   a second coil wound in a second direction, the second direction being opposite the first direction; and   a third coil having a flat plate shape,   wherein the upper core comprises:   a body portion;   a first leg portion and a second leg portion protruding from the body portion; and   a spacing portion formed between the first leg portion and the second leg portion,   wherein the first leg portion comprises two first outer legs and a first center leg disposed between the two first outer legs,   wherein the second leg portion comprises two second outer legs and a second center leg disposed between the two second outer legs,   wherein the first coil is disposed to surround the first center leg, and   wherein the second coil is disposed to surround the second center leg.